package com.woniuxy.shiro.Utils;

import org.apache.shiro.spring.security.interceptor.AuthorizationAttributeSourceAdvisor;
import org.apache.shiro.web.filter.authc.BasicHttpAuthenticationFilter;
import org.apache.shiro.web.mgt.DefaultWebSecurityManager;
import org.springframework.context.annotation.Bean;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * @Description: TODO(用一句话描述这个类的作用)
 * @Author 18452
 * @Date 2021/5/7 19:12
 */
public class JWTFilter extends BasicHttpAuthenticationFilter {

    /*
    * 处理跨域问题
    */
    @Override
    protected boolean preHandle(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        httpServletResponse.setHeader("Access-control-Allow-Origin", httpServletRequest.getHeader("Origin"));
        httpServletResponse.setHeader("Access-control-Allow-Methods", "GET,POST,OPTIONS,PUT,DELETE");
        httpServletResponse.setHeader("Access-control-Allow-Headers", httpServletRequest.getHeader("Access-Control-Request-Headers"));
        //跨域时会首先发送一个option请求,这里我们给option请求返回正常状态
        if(httpServletRequest.getMethod().equals(RequestMethod.OPTIONS.name())){
            httpServletResponse.setStatus(HttpStatus.OK.value());
            return false;
        }
        return super.preHandle(request, response);
    }

    @Override
    protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) {
        if(isLoginAttempt(request, response)){
            try {
                //如果有token
                executeLogin(request, response);
            } catch (Exception e){
                //如果请求头中没有Authorization字段就会到这儿来
                response401(request, response);
            }
        }
        return super.isAccessAllowed(request, response, mappedValue);
    }

    /**
     * 判断请求头中是否有Authorization字段
     * @param request
     * @param response
     * @return
     */
    @Override
    protected boolean isLoginAttempt(ServletRequest request, ServletResponse response) {
        HttpServletRequest httpServletRequest = (HttpServletRequest)request;
        String authorization = httpServletRequest.getHeader("Authorization");
        return authorization != null;
    }

    //开启shiro注解支持
    @Bean
    public AuthorizationAttributeSourceAdvisor authorizationAttributeSourceAdvisor(DefaultWebSecurityManager securityManager) {
        AuthorizationAttributeSourceAdvisor advisor = new
                AuthorizationAttributeSourceAdvisor();
        advisor.setSecurityManager(securityManager);
        return advisor;
    }
    @Override
    protected boolean executeLogin(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = (HttpServletRequest)request;
        //从请求头中获取token
        String authorization = httpServletRequest.getHeader("Authorization");
        //放入对象中, 数据库查询, 等同于UsernamePasswordToken
        MyJWT token = new MyJWT(authorization);
        //提交给realm进行登录,如果错误会抛出异常并且捕获
        System.out.println("JWTFilter.executeLogin交给realm判断:" + token);
        //这个等同于subject.login(token)
        getSubject(request, response).login(token);
        return true;
    }
    /**
     * 将非法请求跳转到 /401
     */
    private void response401(ServletRequest req, ServletResponse resp) {
        try {
            HttpServletResponse httpServletResponse = (HttpServletResponse) resp;
            httpServletResponse.sendRedirect("/401");
        } catch (IOException e) {
            System.err.println(e.getMessage());
        }
    }
}
